1. Technical Field
The present disclosure relates generally to wound dressings for use in a negative pressure wound therapy (NPWT) system. In particular, the disclosure relates to a composite wound dressing that includes a wound filler or packing member affixed to a cover layer to facilitate wound healing and ease the application of the dressing to a wound.
2. Background of Related Art
The body's natural wound healing process is a complex series of events beginning at the moment of injury. Initially the body reacts by delivering proteins and other factors to the wound through the blood stream to minimize the damage. Blood clots to prevent blood loss while cells engulf bacteria and debris to carry it away from the wound site. Next, the body begins to repair itself in a stage of healing often referred to as the proliferate phase. This phase is characterized by the deposition of granulation tissue in the wound bed. Granulation tissue provides a base structure over which cells may migrate inwardly from the periphery to close the wound. Finally the process ends as collagen gives strength to new tissue over time often forming a scar.
One technique for promoting the natural healing process, particularly, but not exclusively during the proliferate phase, is known as negative pressure wound therapy (NPWT). Application of a reduced pressure, e.g. sub-atmospheric, to a localized reservoir over a wound has been found to assist in closing the wound. The reduced pressure may be effective to promote blood flow to the area, to stimulate the formation of granulation tissue and the migration of healthy tissue over the wound by the natural process. Also a reduced pressure may inhibit bacterial growth by assisting in removing fluids exuding from the wound. This technique has proven effective for chronic or non-healing wounds, but has also been used for other purposes such as post-operative wound care.
The general NPWT protocol provides for the introduction of a filler or packing member into the wound, and subsequently applying a cover layer over wound and packing member. The packing member serves to support the cover layer and also to absorb and/or promote fluid transport away from the wound bed. The wound filler may comprise such materials as non-reticulated foams, non-woven fabrics, continuous fibers or gauze. The cover layer may comprise a thin polymeric film that includes an adhesive periphery for forming a substantially fluid tight seal with the healthy skin surrounding the wound. The cover layer thus defines a vacuum reservoir over the wound where a reduced pressure may be maintained over time by the application of individual or cyclic evacuation procedures.
In some instances, applying a packing member and a cover layer individually to a wound may be a time consuming, and labor intensive process. A composite wound dressing that includes a packing member affixed to a cover layer may facilitate the application of the wound dressing to a wound for use in a (NPWT) system.